Hydraulic jack



- T. C. POMEROY HYDRAULIC JAcK Original Filed ,Jan. 22, 1938 June 22,1943.

4 Sheets-Sheet 1 ATTozNEYs E 0 m m June 22, 1943. 1', c, PQMEROY2,322,314

HYDRAULIC JACK Original Filed Jan. 22, 1938 4 Sheets-Sheet 3 El/OIE IONTANK 777///% I AVA/A /NVENTOE 77Mo7-HY C. POMEEOY Arron/vs Y:

June 22, 1943. T. c. POMEROY HYDRAULIC JACK Original Filed Ja n.- 22,1938 4 Sheets-Sheet 4 77Mb'r/1Y Patented June 22, 1943 HYDRAULIC JACKTimothy C. Pomeroy, Long Beach, Calif.

Original application January 22, 1938, Serial No. 186,366, new PatentNo. 2,211,479, dated August 13, 194i). Divided and this application July5, 1940, Serial No. 343,928

1 Claim. (01. 60- 52) This invention relates to new and usefulimprovements in hydraulic jacks, and is a division of my pendingapplication, Serial No. 186,366, now Patent No. 2,211,479.

An object of the present invention is to provide a hydraulic jack havingmeans embodied in the construction thereof, whereby it may be operatedin any position from a vertical to a horizontal position. v

A further object is to provide a hydraulic jack comprising a maincylinder, a reservoir, and an expansion tank, so interconnected that thefluid may be circulated therebetween without the provision of air vents,as is now common practice in most fluid-operated jacks,

A further object of the invention is to provide a hydraulic jackcomprising a cylinder, a reservoir, and an expansion tank and in whichthe expansion tank serves a dual purpose, in that when the plunger ofthe jack is lowered to its normal, or contracted position, the expansiontank acts to receive the overflow from the reservoir, andwhen the jackis operated to lift a load, a vacuum is created in the reservoir, whichdraws the liquid from the expansion tank into the reservoir, against theforce of gravity, because of the circulatory connection between theexpansion tank and reservoir being at their upper ends, and whereby thevacuum in the apparatus becomes greater, as the jack is operated to liftthe load, which materially aids in sealing off the outside atmospherefrom the liquid in the jack, because of the vacuum tending to draw thepacking glands of the jack into tighter contact with their respectiveparts.

Features of the invention reside in the flexible conduits provided inthe expansion tank and reservoir, having weighted heads at their free,unsupported ends adapted to bend said conduits, when the jack issupported at an incline or in a horizontal position, whereby the intakeends of said conduits will be disposed below the level of the liquid insaid tank and reservoir, when the jack is supported on its side, or insubstanmany a horizontal position; in the provision of a hydraulic jackcomprising a reservoir and an expansion tank, neither one of which isprovided with a vent opening, whereby the jack may be placed on its sidewithout danger of the liquid leaking therefrom; and, in the provision ofa hydraulic, leak-proof jack of simple and inexpensive construction.

Other objects of the invention will appear from the followingdescription and accompanying drawings and will be pointed out in theannexed claim.

--In the accompanying drawings there has been disclosed a structuredesigned to carry out the various objects of the invention, but it is tobe understood that the invention is not confined to the exact featuresshown as various changes may be made within the scope of the claim whichfollows.

In the drawings:

Figure 1 is a vertical sectional view substantially on the line I-| ofFigure 3, showing the construction of the main cylinder and plunger andthe means for supporting the operating handle on the base;

Figure 2 is a vertical sectional View substantially-on the line 22 ofFigure 1, showing the means provided within the expansion tank andreservoir, whereby the jack may be operated in a horizontal position, orat any desired angle;

Figure 3 is a sectional plan view on the line 33 of Figure 1, showingthe arrangement of the main cylinder, expansion tank and reservoir onthe pump base;

Figure 4 is a detail sectional View on the line 4-4 of Figure 1, showingthe valve means in normal closed position;

Figure 5 is a similar view, but showing the pump piston actuated to openthe valves;

Figure 6 is a detail sectional view on the line 6 -6 of Figure 5;

Figure 7 is a plan view of the jack on a smaller scale, showing variouspositions of the operating handle of the pump; and

Figure 8 is a view showing the positions assumed by the flexible tubesin the expansion tank and reservoir, when the jack is placed in ahorizontal position.

The novel jack herein disclosed is shown comprising a base, generallyindicated by the numeral 2, preferably having a counterbore 3 therein,adapted to receive the lower end of a main cylinder 4. The lower end ofthe cylinder has secured therein a plug or closure member 5 having adepending cylindrical portion 6 adapted to be received in a relativelysmaller counterbore 1, axially alined with the main cylinder.

The upper end of the cylinder is shown closed by means of a sealingmember 8 having a conical surface 9 adapted to engage a correspondinglyshaped seat ll provided at the upper edge of the cylinder wall. Themember 8 has an inwardly extending flange l2 bored to receive theplunger 13, which is tubular, as clearly illustrated in Figures '1 and3. A suitable packing l4 is seated on the flange l2. A gland I5 isseated against the upper face of the packing l4 and is adapted to beforced downwardly by a cap [6, received in threaded engagement with theupper end of the cylinder, as clearly illustrated in Figure 1. The capI6 is bored to receive the reduced upper end ll of the gland I5, and thegland, in turn, is bored to receive the plunger I3 and cooperates withthe member l2 to guide the upper end of the plunger in its reciprocalmovement.

A load-engaging element 18 is fitted into the upper end of the plunger[3 and provides a cap therefor. The lifting element is provided with athreaded socket for receiving the upper end of a tie rod or bolt IS, thelower end of which is exteriorly threaded to receive a nut 2|.

A plunger head, generally indicated by the numeral 22, is secured to thelower end of the plunger l3, and is shown comprising a disk-like memberpreferably having a shallow counterbore in its upper surface forreceiving the lower end of the plunger 13. A cup-shaped packing 24 isseated against the bottom face of the member 23,

and is preferably provided with a suitable retainer 25, of resilientmaterial, for yieldably holding the peripheral flange of the packing 24in sealing contact with the walls of the cylinder 4. A suitable washer26 is interposed between the retainer and the nut 2!, whereby thehorizontal wall of the packing may be tightly clamped against the member23 by rotation of the nut 2|.

A suitable relief valve 21 is provided in the lowermost end of the tierod IQ of the plunger and is normally retained on its seat by a suitablespring element 28, secured to the lower terminal of the rod [9 bysuitable screws, as illustrated in Figure 1. A fluid duct 29 leads fromthe valve 2? to a transverse opening 3| provided in the rod l8,immediately above the member 23. Suitable openings 32 are provided inthe Wall of the plunger 3 at its lower end and are alined with theopening 3| in the rod 19. V

An actuating bar 33 is received in the alined openings 3i and 32, andhas its ends disposed in close proximity to the walls of the cylinder 4.The actuating bar 33 rests upon the upper end of a pin 34, whose lowerend engages the relief valve 21'. The means 28 for yieldably holding therelief valve 2'! on its seat has sufficient tension to overcome theweight of the actuating bar 33 and pin 24 so as to normally hold thevalve 21 on its seat, as will readily be understood by reference toFigure l. The purpose of the relief valve 21 will subsequently bedescribed.

An important feature of the present invention resides in the fluidretaining means of the jack which, as best illustrated in Figures 2 and3, comprises a reservoir 35 and an expansion tank 36, interconnected attheir upper ends by a suitable by-pass or cross duct 31, provided in acap 38 preferably having annular grooves 39 in its lower face adapted toreceive the upper ends of the expansion tank 36 and reservoir 35, asclearly illustrated in Figure 2. Suitable gaskets 4| are seated in thebottoms of the grooves 39 and are engaged by the upper ends of theexpansion tank and reservoir to prevent leakage therebetween.

The lower ends of the reservoir and expansion tank 35 and 36 are shownseated on gaskets 42 supported in shallow counterbores provided in thebase 2. Suitable tie rods 43 are shown extending lengthwise through theexpansion tank 36 and reservoir 35, and have their lower ends receivedin threaded engagement with the base 2,

iii!

as clearly illustrated at 44 in Figure 2. The upper ends of the tie rods43 are received in apertures provided in the cap 38, and preferably haveheads 45, whereby the rods 43 may be conveniently rotated to securelyfasten the expansion tank and reservoir to the base in leak-tightrelation.

The means for controlling the circulation of fluid to an from the maincylinder is best illustrated in Figure l, and comprises a pump, enerallyindicated by the numeral 46. The pump comprises a cylinder 4? having asuitable base 48 fitted to and secured tothe base 2 of the jack bysuitable bolts 49, best illustrated in Figures 4 and 5. The pumpcylinder 47 has a piston 5| mounted for reciprocal movement therein,which projects from the upper end of the cylinder. Leakage is preventedaround the piston by a suitable gland 52 and packing 53, received in acounterbore 54 in the upper end of a cylinder and secured therein by asuitable cap 55, received in threaded engagement with the upper end ofthe cylinder 41. A suitable locking nut 56 is also received in threadedengagement with the upper end of the cylinder 4?. This nut secures thecap in adjusted position, whereby the desired sealing engagement betweenthe packing glands 52 and 53 and the piston 55 may be obtained.

Means is provided in the lower portion of the pump for controllingcirculation of the fluid therethrough. As best illustrated in Figures 4and 5, the bore 5'! of the cylinder communicates at its lower end withoppositely disposed, axially alined valve chambers 58 and 59. A suitablecheck valve 6| is mounted in the valve chamber 58 and normall closes theupper end of a port 32. A spring 63 is preferably provided forconstantly urging the valve 6| into engagement with its seat. The lowerend of the port 62 communicates with one end of a horizontal duct 64,the opposite end of which is in direct communication with one end of aflexible intake tube 65, whose lower end is secured to the base 2 by asuitable fitting 65. The flexible tube 65 extends upwardly into thereservoir 35 and has a weighted head 61, the upper end of whichterminates at or near the intermediate portion of the reservoir 35. Theflexible tube 65 forms an important part of the present invention, aswill be susequently described.

A check valve 68 is also provided in the valve chamber 59, and isnormally engaged with a seat 69 by a suitable spring 1 I. A verticalduct 12 has its upper end communicating with the valve chamber 59 andits lower end with one end of a horizontal duct 13, whose opposite endis in direct communication with a duct 14. The duct 14 is connected atits opposite end to an annular passage 15, provided in the lower reducedportion 6 of the member 5 of the main cylinder 4. One or more transverseducts 16 are provided in the reduced portion 6 of the lower end of themain cylinder, and are in direct communication with the annular channel15 provided therein. A small duct 11 establishes communication betweenthe transverse duct 16 and the counterbore 18,

provided in the member 5 of the main cylinder. This counterbore is incommunication with the lower end of the cylinder beneath the piston head22, so that when fluid is pumped into the lower end of the cylinderbeneath the head 22, the latter will be elevated, as will readily beunderstood.

Means is provided for operating the pump piston 5| and also, wherebysaid piston may be locked against axial movement to prevent lowering ofthe plunger l3, when supporting a load. As

shown in Figure 1, the upper end of the pump piston is pivotallyconnected to a member or head 19, by a horizontally disposed pivot pin'85 An operating handle 8| is secured at one end to the member 19. Aconnecting element 83 has one end pivotally connected to the head 19 bya vertically disposed pivot pin 86. The axis of the pivot pin 86intersects the axis of the pivot 80, and the latter provides the axisabout which the head 79 swings. The opposite end of the element 83 ispreferably forked, as shown in Figures 1 and 2, and said forked end ispivotally connected to the upper end of an arm 84, by a hori zontallydisposed pin 90. The lower end of the arm 84 is pivotally mounted on thebase 2 of the jack substantially between the expansion tank 36 andreservoir 35, as clearly illustrated at 85.

The above described mechanism provides a pivotal support for the handle8| and also a locking means whereby the piston may be locked againstrotary movement, thereby to prevent accidental actuation of the valvemechanism, when the jack is supporting a load. To thus lock the pistonagainst rotary movement, the operating handle Bl is moved to an inclinedposition, either above or below the horizontal, as indicated by thedotted lines in Figure 1, whereby the handle cannot be swung toa lateralposition, as shown in full and dotted lines in Figure '7, to relativelyrotate the piston and thereby unseat the check Thus, it will be seenthat the operating handle 8| has the dual function of operating thepiston -5| and also unseating the valves to release the fluid from thelower end of the cylinder.

This is a Very desirable feature in that it necessitates but a singleoperating member for performing these two functions.

. To operate the piston 5|, the operating handle 8| must besubstantially in its intermediate or horizontal position, as shown infull lines in Figure 1 and the dotted lines C in Figure '7. When thuspositioned, the axes of the pivots as and 90 because of the fluidaccidentally being released from the lower end of the cylinder 4. Ifdesired, suitable means, not shown, may be provided for positivelysecuring the handle in looking position.

Means is provided for actuating the valves 6| and 68 in the lowerportion of the pump, whereby these valves may be forcibly unseated,thereby to permit the fluid to return from the lower end of the cylinderbeneath the piston head 22, to the reservoir 35.

To thus open the valves BI and 68, a pair of thrust elements 87 and 88are mounted in the valv chambers 58 and 59, respectively, and eachnormally has one end projectin into the bore 51 of the cylinder 41, asbest illustrated in Figure 4;. These thrust members are spring-actuated,and are preferably tubular, as shown. Each has a suitable spring 89mounted therein, and the inner ends of these springs engage pins 9|secured in the adjacent ends of the thrust members, as best illustratedin Figure 4. The opposite ends of the springs 89 are seated against pins92 having their terminals supported in a pair of fixed sleeves 93 and 9Bof the valve chambers 58 and 59, respectively. The outward terminals ofthe thrust members 8'! and 88 are preferably beveled, as shown, wherebysaid ends may readily be inserted between the check valves and theirrespective seats, when the thrust members are moved in oppositedirections, by the lower end of the piston 5|, as will readily beunderstood by reference to Figure 6. The valve BI is preferably openedslightly in advance of the valve 68.

As shown in Figures 4 and 6, the piston 5| has its lower end portion 9 1flattened, whereby when the piston 5| is turned to the position shown inFigure 5, the thrust members 81 and 88 will be thrust outwardly. Whenthese members are thus thrust outwardly, their outer ends will engagethe check valves 6| and 58 and unseat them, as clearly illustrated inFigure 5.

-When the flattened terminal 94 of the piston 5| is returned to itsnormal position, as shown in Figure 4, the thrust members 8'! and 88will return to their normal positions by the action of the springs 89,and thus permit the valves 6| and 68 to return to their respectiveseats,

and thereby render the pump operative to pump fluid from the reservoirinto the lower end of the cylinder 4 beneath the piston head 22.

Means is also provided for establishing communication between the upperend of the cylinder 4 and the lower end of the reservoir 35, andcomprises a relatively small tube 95 having its upper end connected tothe interior of the cylinder 4 by a suitable fitting 96. The lower endof the tube 95 has a suitable fitting 91 connecting it to one end of ahorizontal duct 98 provided in the base 2 of the jack. The opposite endof the duct 98 communicates with the lower end of the reservoir 35, asclearly illustrated in Figure 3.

Another feature of the invention resides in the provision of a flexibletube I00 within the expansion tank 35, which has its upper end securedto the head 38 by a suitable fitting 99. This fitting is in directcommunication with the by-pass 31 in the head 38, which establishescommunication between the interiors of the reservoir 35 and theexpansion tank 36. The lower end of the flexible tube lilii has aweighted head ||l| whose lower end is disposed in close proximity to thebottom wall of the expansion tank, as best illustrated in Figure 2.

Before operating the jack, enough fluid is introduced into the jack tocompletely fill the reservoir 35 and partially fill the expansion tank36, when the plunger head 22 is in its lowermost position, as shown inFigure 1. The jack handle 8| is then oscillated in substantially avertical plane, whereupon fluid is drawn into the pump cylinder 41 fromthe reservoir 35 through the ducts 62 and 54. When the piston 5| isthrust downwardly, the fluid drawn into the pump cylinder through thevalve BI is forced through the valve chamber 59, thereby unseating thevalve 68. From the valve chamber 59, the fluid flows through the ductsl2, l3 and 14, into the lower end of the main cylinder 4, as willreadily be understood. Upon continued oscillation of the handle 8|, thefluid will continue to flow into the lower end of the cylinder 4 beneaththe plunger head 22, thereby causing the plunger l3 to elevate the load,until the operation of the pump is interrupted.

If the operator fails to cease pumping, when the plunger approaches thelimit of its upward movement, the actuating bar 33, carried by theplunger, will subsequently engage the bottom surface of the member I2,whereby the bar 33 is moved downwardly relatively to the plunger, andthereby unseats the release valve 21. Such actuation of the releasevalve will permit the fluid pumped into the cylinder beneath the pistonhead 22, to by-pass or escape through the port 29 in the piston head,into the cylinder above the piston head, whence it returns to thereservoir 35, through the tube 95.

If the operator continues to oscillate the pump handle, a portion of thefluid returned to the reservoir may, when the reservoir is subsequentlyfilled, by-pass over into the expansion tank through the horizontal duct31 provided at the upper ends of the expansion tank and reservoir.

From the foregoing, it will readily be understood that the hereindescribed jack is substantially fool-proof in operation, because, by theprovision of the reservoir 35 and expansion tank 36, there is verylittle danger of the jack becoming inoperative because of the lack offluid pressure, There is always enough fluid in the apparatus to assureeflicient operation thereof provided, of course, that the fluidcontained in the jack does not escape or leak therefrom.

Leakage of the liquid from the apparatus is sub stantially eliminated asa result of the vacuum which is created in the apparatus, when the jackis operated to elevate a load. This vacuum becomes greater as the jackis operated to lift the load, and thereby tends to draw the packingglands into tighter sealing engagement with their respective parts,whereby the liquid cannot escape from the jack, even when the jack issup porting a heavy load.

The flexible tubes 65 and I provided in the reservoir 35 and expansiontank 36, respectively, provide means whereby the jack maybe operated atany angle, or in a horizontal position, as illustrated in Figure 8. Inthis figure, it will be seen that when the jack is placed in a horizontal position, the tubes 55 and I00 will bend or flex by gravity,whereby their weighted heads will rest upon the lowermost portions ofthe walls of the reservoir. and expansion tank There is suflicient oilin the reservoir so that the level of the oil therein, when the jack isplaced in a horizontal position, will be substantially above the head 61of the intake tube 65.

The flexible tubes 65 and I00, therefore, greatly extend the usefulnessof the jack in that they make it possible to operate the jack, whenplaced at an angle, or when in a horizontal position which, heretofore,has been impossible with hydraulic jacks of conventional construction.

The lower end of the flexible tube I00 is disposed in close proximity tothe bottom of the expansion tank, so that as the fluid is pumped fromthe reservoir into the lower end of the main cylinder, in the operationof elevating the plunger I3, a portion of the fluid in the expansiontank may be drawn upwardly through the tube I00 and into the reservoirby the vacuum which is created in the upper portion of the reservoirabove the level of the fluid therein. The

reservoir and expansion tank are so proportioned that there is ampleroom for the transfer of the fluid therebetween and to and from the mainIn a hydraulic jack, a cylinder, a plunger therein, an inelastic fluid,a reservoir, a valved passage connecting the bottom of reservoir to thecylinder, an expansion tank disposed adjacent to the reservoir, a fluidpassage connecting the upper ends of the reservoir and expansion tank, apump for pumping fluid from the reservoir through the valved passage tothe cylinder to elevate the plunger, the intake of said valved passagehaving one end of a flexible tube connected thereto, said tube beingmounted in the bottom of the reservoir and extending upwardly thereinand having a weighted head, whereby the tube will flex or bend when thejack is placed in an inclined or horizontal position, thereby to retainthe intake end of said flexible tube beneath the level of the fluid inthe reservoir, and the fluid passage connecting the upper ends of thereservoir and expansion tank having a flexible tube connected theretoand extending -downwardly into the expansion tank with its

